This invention relates to configuration management for a storage system, and more particularly to a configuration optimization method for a storage system.
In recent years, there is a rapid increase in data amount to be handled by a company or an individual. Along with this, a storage system using a technology such as a storage area network (SAN) or a network attached storage (NAS) is widely used. According to the technology, a storage subsystem or a host computer is coupled via a switch or a hub, to thereby manage data with flexibility.
Further, in these days, along with the increase in size and the enhancement in performance of a storage system (hereinafter, also referred to as storage subsystem), power consumption in the storage subsystem is increasing than ever, due to which greater importance is placed on the attainment of low power consumption in the storage subsystem. Also, with the increase in management cost of the storage subsystem, it has also become increasingly important to reduce the management cost of the storage subsystem.
As regards the attainment of low power consumption in the storage subsystem, there is a technology in which, in a case where a host computer using a storage region (hereinafter, referred to as “volume”) of the storage subsystem has not accessed the volume for a predetermined time period, the power of a physical disk forming the volume is turned off or set to a power saving state (hereinafter, both of the states are collectively referred to as “sleep state”) and when the volume is accessed the sleep state of the physical disk is canceled to recover a normal power state, thereby suppressing power consumption in the storage subsystem.
For example, there is known a technology of performing ON/OFF control of the power of a physical disk which forms a volume provided by the storage subsystem, based on an instruction from a computer coupled to the storage subsystem, as disclosed in, for example, JP 2005-157710 A.
Meanwhile, as regards the cost reduction of the storage subsystem, there is known a technology of allocating a hypothetical volume (hereinafter, referred to as “virtual volume”) to a host computer, and allocating an actual storage region according to an I/O made by the host computer with respect to the virtual volume, as disclosed in, for example, JP 2003-15915 A.
In the case of using the above-mentioned technologies, an administrator of the storage system registers at least one volume for a logical group, which is referred to as pool (hereinafter, a volume registered for the pool is referred to as “pool volume”). At this time, the administrator also sets a threshold value, based on which a capacity shortage of the pool is warned. Then, the administrator creates a virtual volume, and associates the virtual volume with the pool volume and the host computer.
When data is written by the host computer to the virtual volume, the written data is actually stored in the pool volume. When an amount actually used in the capacity of the pool volume approaches the threshold value as a result of data writes made to the virtual volume, the management computer notifies a warning to the administrator. In response to the warning, the administrator performs a process of, for example, adding a physical disk to the storage subsystem.